Seawater carbonate chemistry and photosynthesis and photochemical efficiency of Porolithon onkodes

• Main Authors: Briggs, Amy A, Carpenter, Robert C
• Format: Dataset
• Language: English
• Published: PANGAEA - Data Publisher for Earth & Environmental Science 2019
• Subjects: Benthos; Calcification/Dissolution; Coast and continental shelf; Containers and aquaria 20-1000 L or < 1 m**2; Laboratory experiment; Light; Macroalgae; Plantae; Porolithon onkodes; Primary production/Photosynthesis; Respiration; Rhodophyta; Single species; South Pacific; Tropical; Type; Species; Registration number of species; Uniform resource locator/link to reference; Experiment; Identification; Treatment; Surface area; Calcification rate of calcium carbonate; Net photosynthesis rate, oxygen; Respiration rate, oxygen; Gross photosynthesis rate, oxygen; Irradiance; Slope; Fluorescence, minimum; Fluorescence, maximum; Maximum photochemical quantum yield of photosystem II; Maximum gross photosynthesis rate, oxygen; Initial slope of the photosynthesis-irradiance curve; Light saturation; Temperature, water; Temperature, water, standard error; Alkalinity, total; Alkalinity, total, standard error; pH; pH, standard error; Partial pressure of carbon dioxide water at sea surface temperature wet air; Partial pressure of carbon dioxide water at sea surface temperature wet air, standard error; Bicarbonate ion; Bicarbonate ion, standard error; Carbonate ion; Carbonate ion, standard error; Calcite saturation state; Calcite saturation state, standard error; Irradiance, standard error; Salinity; Salinity, standard error; Carbonate system computation flag; Carbon dioxide; Fugacity of carbon dioxide water at sea surface temperature wet air; Carbon, inorganic, dissolved; Aragonite saturation state; Potentiometric titration; Potentiometric; Calculated using seacarb; Calculated using seacarb after Nisumaa et al. 2010; Ocean Acidification International Coordination Centre OA-ICC; Pacific; Ocean acidification
• Online Access: https://dx.doi.org/10.1594/pangaea.920025; https://doi.pangaea.de/10.1594/PANGAEA.920025

Ocean acidification (OA) is predicted to enhance photosynthesis in many marine taxa. However, photophysiology has multiple components that OA may affect differently, especially under different light environments, with potentially contrasting consequences for photosynthetic performance. Furthermore, because photosynthesis affects energetic budgets and internal acid-base dynamics, changes in it due to OA or light could mediate the sensitivity of other biological processes to OA (e.g. respiration and calcification). To better understand these effects, we conducted experiments on Porolithon onkodes, a common crustose coralline alga in Pacific coral reefs, crossing pCO2 and light treatments. Results indicate OA inhibited some aspects of photophysiology (maximum photochemical efficiency), facilitated others (alpha, the responsiveness of photosynthesis to sub-saturating light), and had no effect on others (maximum gross photosynthesis), with the first two effects depending on treatment light level. Light also exacerbated the increase in dark-adapted respiration under OA, but did not alter the decline in calcification. Light-adapted respiration did not respond to OA, potentially due to indirect effects of photosynthesis. Combined, results indicate OA will interact with light to alter energetic budgets and potentially resource allocation among photosynthetic processes in P. onkodes, likely shifting its light tolerance, and constraining it to a narrower range of light environments. : In order to allow full comparability with other ocean acidification data sets, the R package seacarb (Gattuso et al, 2019) was used to compute a complete and consistent set of carbonate system variables, as described by Nisumaa et al. (2010). In this dataset the original values were archived in addition with the recalculated parameters (see related PI). The date of carbonate chemistry calculation by seacarb is 2020-07-07.